On Fri, 22 Nov 2024, Louis Chauvet <louis.chauvet@xxxxxxxxxxx> wrote:
> To properly test the EDID reading without using the DRM override, add an
> option to configure the EDID for a connector.
>
> Signed-off-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx>
> ---
> drivers/gpu/drm/vkms/vkms_config.c | 1 +
> drivers/gpu/drm/vkms/vkms_config.h | 2 ++
> drivers/gpu/drm/vkms/vkms_output.c | 37 ++++++++++++++++++++++++++++++++++---
> 3 files changed, 37 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/vkms/vkms_config.c b/drivers/gpu/drm/vkms/vkms_config.c
> index ac1a9658c5075c118d59da965ca3392355ccb2b2..1a1234d4f10fa8e5ea6bd649139ecc10c991f875 100644
> --- a/drivers/gpu/drm/vkms/vkms_config.c
> +++ b/drivers/gpu/drm/vkms/vkms_config.c
> @@ -199,6 +199,7 @@ struct vkms_config_connector *vkms_config_create_connector(struct vkms_config *v
> xa_init_flags(&vkms_config_connector->possible_encoders, XA_FLAGS_ALLOC);
> vkms_config_connector->type = DRM_MODE_CONNECTOR_VIRTUAL;
> vkms_config_connector->status = connector_status_unknown;
> + vkms_config_connector->edid_blob_len = 0;
>
> return vkms_config_connector;
> }
> diff --git a/drivers/gpu/drm/vkms/vkms_config.h b/drivers/gpu/drm/vkms/vkms_config.h
> index bba56c9d8aeceac97a4339ef42ab663c5dc54e65..1220b16f6c98d1ebb0ae55d662a84fe25e1a6a02 100644
> --- a/drivers/gpu/drm/vkms/vkms_config.h
> +++ b/drivers/gpu/drm/vkms/vkms_config.h
> @@ -112,6 +112,8 @@ struct vkms_config_connector {
> struct xarray possible_encoders;
> int type;
> enum drm_connector_status status;
> + char edid_blob[PAGE_SIZE];
> + int edid_blob_len;
>
> /* Internal usage */
> struct drm_connector *connector;
> diff --git a/drivers/gpu/drm/vkms/vkms_output.c b/drivers/gpu/drm/vkms/vkms_output.c
> index fc6a0cdade0739b94820ed4e0924cf355137fe79..56590afb33d75465971d10a282040690840cdbee 100644
> --- a/drivers/gpu/drm/vkms/vkms_output.c
> +++ b/drivers/gpu/drm/vkms/vkms_output.c
> @@ -31,13 +31,44 @@ static const struct drm_connector_funcs vkms_connector_funcs = {
> .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> };
>
> +static int vkms_connector_read_block(void *context, u8 *buf, unsigned int block, size_t len)
> +{
> + struct vkms_config_connector *config = context;
> +
> + if (block * len + len > config->edid_blob_len)
The parameters to the read block function are a bit weird for historical
reasons. The start offset is indicated by block number, length by
len. The start byte offset is thus block * EDID_LENGTH! There's no
smaller granularity for start offset. However len can be < EDID_LENGTH!
So the above should be (block * EDID_LENGTH + len > edid_blob_len)
> + return 1;
> + memcpy(buf, &config->edid_blob[block * len], len);
And this should be &config->edid_blob[block * EDID_LENGTH].
(Your patch would work, but just by coincidence due to the way the read
block function is currently called.)
> + return 0;
> +}
> +
> static int vkms_conn_get_modes(struct drm_connector *connector)
> {
> + const struct drm_edid *drm_edid = NULL;
> int count;
> + struct vkms_config_connector *connector_cfg;
> + struct vkms_device *vkmsdev = drm_device_to_vkms_device(connector->dev);
> + struct vkms_config_connector *context = NULL;
> +
> + list_for_each_entry(connector_cfg, &vkmsdev->config->connectors, link) {
> + if (connector_cfg->connector == connector) {
> + context = connector_cfg;
> + break;
> + }
> + }
> + if (context)
> + drm_edid = drm_edid_read_custom(connector, vkms_connector_read_block, context);
Thanks for using drm_edid_read_custom() for this btw!
> +
> + /*
> + * Unconditionally update the connector. If the EDID was read
> + * successfully, fill in the connector information derived from the
> + * EDID. Otherwise, if the EDID is NULL, clear the connector
> + * information.
> + */
> + drm_edid_connector_update(connector, drm_edid);
> +
> + count = drm_edid_connector_add_modes(connector);
>
> - /* Use the default modes list from DRM */
> - count = drm_add_modes_noedid(connector, XRES_MAX, YRES_MAX);
> - drm_set_preferred_mode(connector, XRES_DEF, YRES_DEF);
I don't really know anything about your use case, but don't you want to
fall back to the above for drm_edid == NULL? *shrug*
BR,
Jani.
> + drm_edid_free(drm_edid);
>
> return count;
> }
--
Jani Nikula, Intel
